</font><font color="blue" class="small">( the return line if it was clogged would not collapse the plastic bowl, it MAY blow the line between the pump and the return to tank, but that should not effect the bowl at all. SUCTION means that there is a blockage between the fuel getting IN to the bowl and the fuel storage location. (in the JINMA case that is only 2 things) the Valve and that screen.)
fuel blockage in the return line would actually slow the suction of fuel down as the pump would then have to pump higher pressure which means LESS flow and LESS suction on the bowl.... )</font>
I've already agreed that odds favor screen blockage above the sediment bowl. But I get the feeling you don't quite have a handle on the physics of fuel flow here. Rather than a modern pusher pump in the tank, Jinma still uses the old method where a remote fuel pump obtains fuel by suction (with a little help from gravity). When fuel is removed from a (sealed) tank, a vacuum is created - unless something (air) is introduced to replace the missing fuel. This used to be the function of vented fuel caps, but the EPA put an end to that.
An obvious function of the return line is to route excess fuel back to the tank. But obviously not as much is returned as is removed, so there still the matter of vacuum to deal with. A very important second function of the return line then, is to vent the tank.
If sufficient venting doesn't occur, the Venturi principle takes over. Remember the Venturi principle? It's what keeps liquid in a straw till you take your finger off the top. It's what makes your garden hose sometimes look like it "went flat". It's what picks up things on some assembly lines. Stop the IN, you get no OUT.
Try it yourself. With the fuel cap sealed tight on the fill neck, shut off the fuel flow at the petcock. Remove the sediment bowl, then remove the return line at the tank end. Open the petcock, fuel will flow. Put your finger over the tanks return hole, the fuel flow will stop.
But the FP isn't smart enough to know if/when the vent is blocked, even though the supply of fuel has stopped. As long as the engine continues to run on what's the fuel filter supply, the FP will continue it's attempt to obtain fuel from the tank that has stopped delivery because of the Venturi effect.
Metal tank, reinforced rubber hose, plastic sediment bowl: which one do you think is going to give up first?
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For Eric
Right in the middle of your photo
is a little gold colored cylinder looking thing. That's the screen that we're talking about. It's going to be messy, but you'll have to remove the sediment bowl housing from the tank to get at it. You can buy replacement screens or screen material at most farm supply stores. But since you're going to lose fuel doing this anyway, I think you should take the opportunity to clean out the tank so this screen business doesn't become repetitive. With luck, they might also have a replacement sediment bowl and gasket of comparable diameter.
Your other photo shows a very black looking sediment bowl, indicating it's been a long time since the owner dumped the dirt. I make it a point to check the sediment bowl before I ever start up a cold tractor. If there's any dirt and/or water visible, it gets dumped BEFORE the tractor gets started.
//greg//
